Share a Keyboard/Mouse Between Multiple Computers With x2x

If you have multiple computers on your desktop there are a number of
scenarios for using them:

The brute force way: get a big desk and a swivel chair and spin back and
forth between keyboards/mice

Use VNC or rdesktop to control secondary computers from your primary
computer. The main problem with this is that you lose all the screen real
estate on your secondary computers and end up with their desktops showing in
a window on your primary computer.

Get a KVM to allow you to switch one keyboard/mouse between multiple
computers.
The normal usage of a KVM is to switch your monitor as well as
your keyboard and mouse, but that's not required.
KVM's often seem like a great solution for many peripheral
sharing problems, but they're a bit of a hit-or-miss. They often have switching
problems, system boot problems, video quality problems, and if you use
multiple monitors a KVM to switch multiple monitors between
systems gets pretty expensive.

Use x2x, the solution we'll examine here,
to share the keyboard and mouse between systems.

There are two ways to run x2x on Linux, the easiest is to use
ssh with X forwarding enabled and ssh from the primary system
to the secondary system and run x2x on the secondary system:

primary $ ssh -X secondary x2x -east -to :0

The -X option tells ssh to enable X forwarding. The "x2x ..."
tells ssh to run x2x on the remote system (secondary) rather than running the shell.
The "-east" option tells x2x where one system is relative to the other:
to the east or west (-west).

The primary system is the system whose keyboard and mouse you are
actually using. The secondary system is the one that is going to share the primary
system's keyboard and mouse.

Now, if you move the mouse on the primary system over to the edge
where the secondary system is the mouse pointer should move from the primary screen
to the secondary screen and from now on any mouse movement should
be passed to the secondary system and anything you type on the keyboard
should be sent to the secondary system.
If this doesn't work try moving the mouse to the other side of the screen,
if that works then restart the command using "-west" rather than "-east".

The other method of running x2x
on a Linux system is to run it directly on the primary system and tell it
to connect to the X server on the secondary system:

primary $ x2x -to secondary:0.0 -east

The reason this is not the easy method is that you also need to enable
remote X access on the secondary system using xhost:

secondary $ xhost primary

and you also need to open TCP port 6000 on both systems. The easiest way of
doing this is going to depend on your distro.

The main advantage of the second method is that copy/paste will now
work between systems.

Getting x2x to work on a Windoze system takes a bit more work,
mostly because first you have to install Cygwin. Although, if you're a Linux
fan you should already have it installed, it's the only way to make Windoze bearable.
When you're installing Cygwin make sure x2x
is selected in the list of available packages.

Using x2x with Cygwin has a couple of restrictions/problems:

You can't use the ssh connection method.

You have to use the Windoze system as the primary system (i.e.
you have to use the keyboard and mouse on the Windoze system).

If you have multiple displays on your Windoze system you'll
probably experience mouse problems when you return the mouse from a
secondary display. The only workaround is to move the mouse very
very slowly when you're about to move off a secondary display onto the
primary display.

When using x2x on Windoze run the following command from a shell prompt:

windoze $ x2x -fromwin -to secondary:0.0 -east

Generally speaking x2x works very well both on Linux
and on Windoze.
Every once in a while you may get a bit of mouse flakiness
when you move a window on a secondary display.
Also once in a while, when using the shift key you may get the
unshifted character on the secondary system if you type too fast.
But in most instances you won't notice any difference between typing/mousing
on the primary system and on the secondary system.

p.s. If you have a problem where you get a ">" when you type "<" you need to
find a newer version of x2x.
This is long-standing bug that was recently fixed.

I started using Synergy when I saw it mentioned on Tech-TV. I had Synergy working between WindowsXP, Linux (CentOS), and UNIX (IRIX). The nicest feature was cutting-and-pasting between the computers. BUT that was 2 jobs and 3 years ago.

The latest release of Synergy on Sourceforge was April 2006. Is the project dead or is it only a long time between releases? If the project is dead it's only a matter of time before obsolescence creeps in and Synergy is no longer useful.

I just checked and the latest Freshmeat release of x2x is from Sept. 2005. The page also says, "we are looking for brave person who can read and understand whole x2x and will write new x2x".

The original Synergy is dead, but people have continued it. The Windoze project is Synergy+, and for Mac there's SynergyKM. SynergyKM is awesome, it integrates straight into your Mac System Preferences and is extremely easy to use.

I have server on Windoze and client on Gentoo and for me it doesn't even work unless it's started under root privileges (the synergyc). And even then left-arrow and down-arrow are not automatically repeated (haven't noticed problems with other keys) on the client end. Which is a real pain in the ass if you are trying to code something longer than 15 lines.

I use synergy between Fedora and XP - with a microsoft multimedia type keyboard. It took a bit of poking around but some of my issues were just getting the keyboard set up correctly for KDE. Once I did that everything worked great - even the volume keys - and other special keys to launch email, browser, etc. It really is the ultimate solution I've found for sharing keyboard and mouse.

It does run into issues sometimes, or can get bogged down if the machine running as the server comes under a really heavy load - but I would imagine this would be the case with any software doing the same type of thing. The ability to copy and paste between machines is so cool I can't even begin to think what it would be like not to have that.

A much easier way to share mouse and keyboard is by using synergy. It works fine on linux and on windoze too. If you want to get the connection secure you have to work with a ssh-tunnel. Copy/Paste between the 2 systems works as well.